The invention relates to a clamping device on a grinding spindle rotor and to a rotary part with a centering device.
Such a clamping device is known from DE 33 22 258 C1. The area of application for such clamping devices and grinding spindle rotors are primarily circular and non-circular grinding machines, for example, universal grinding machines with which high-quality machine parts are ground. This demands the highest dimensional accuracy and flawless surface quality. The grinding machines in serial production for grinding shaft parts as well as camshafts and crankshafts are an especially important example. However, other grinding machines can be used if high demands are placed on the grinding result.
In the case of DE 33 22 258 C1, the rotary part to be clamped on the grinding spindle rotor is a grinding wheel that comprises a base body and an abrasive layer applied circumferentially thereto. The base body of the grinding wheel has an interior recess from which three grooves run radially outward. These three grooves are situated at a regular 120-degree angular interval from one another. With this interior recess, the rotary part is placed onto a centering section of the grinding spindle rotor, and there, is clamped securely in the axial direction between a positioning flange of the grinding spindle rotor and a clamping flange. The centering section has a largely cylindrical basic shape, however, including three uniformly spaced splines projecting radially outward from the exterior circumference of the centering section. The exterior diameter of the splines is the same as the interior diameter of the interior recess in the rotary part outside of the axis-parallel grooves. The splines thus form three positioning bodies with which the centering section is centered on the interior recess of the rotary part.
This known clamping device is intended to facilitate placement of the rotary part onto the centering section while simultaneously attaining precise centering. Specifically, the grooves of the rotary part are aligned on the splines of the centering section for placing the rotary part thereon. The splines have a larger radial distance from the groove base of the grooves embodied in the interior recess of the rotary part. Since the splines also have a smaller circumferential extension than the grooves, consequently there is no simple way to place the rotary part onto the centering section with an exact angular alignment. As soon as a planar side of the rotary body is positioned against the positioning flange of the grinding spindle rotor, the rotary body is turned so that the splines now are positioned to fit on the cylindrical interior recess of the rotary part, which recess has a smaller diameter than the groove base of the three grooves. The rotary body is thus securely centered on the centering section.
The clamping device in accordance with DE 33 22 258 C1 fulfills its purpose and has proved itself in practice. However, when placing the rotary body on the centering section, attention must be paid to the exact angular alignment of both parts. In addition, the suitable fit between the three splines that form the support body and the interior diameter of the interior recess still requires a compromise. While there should be precise centering so that there is the closest possible fit, attachment, which also includes the final rotation, should also be as easy as possible. Thus, there is a need for facilitated operability of the known clamping device with even more precise centering.
DE 34 05 556 C1 describes a clamping device for a grinding ring that has a detachably mounted clamping flange on a carrying flange. The bearing pin on which the grinding ring is placed and is to be clamped has a plurality of splines running across a length thereof and projecting in the radial direction. Embodied in the interior bore of the grinding ring are correspondingly formed grooves that are allocated to each of the splines. The cross-sectional profile of the projecting splines has the contour of a circular arc with a radius having a center of curvature which is offset by an eccentricity from the center point of the bearing pin. Thus, although precise centering with tight clearance is possible due to relatively broad radial tolerances, in terms of production engineering the production of a circular spline on the contour, the center of curvature of which is arranged eccentrically, is complex and demanding, especially since corresponding recesses that fit the splines must be provided in the interior bore of the grinding ring.
The underlying object of the invention is therefore to improve the known clamping device in such a manner that joining the grinding wheel rotor and rotary part is as simple as possible and is done with a low expenditure of force, while at the same time centering occurs in a manner that is absolutely certain and highly precise. Moreover, production should be as cost-effective as possible, in particular for wide grinding wheels or wide grinding wheel sets with long centering sections required therefor.